void CopyablePolymorphic::VisitDecl(clang::Decl *decl)
{
CXXRecordDecl *record = dyn_cast<CXXRecordDecl>(decl);
if (!record || !record->hasDefinition() || record->getDefinition() != record || !record->isPolymorphic())
return;
CXXConstructorDecl *copyCtor = Utils::copyCtor(record);
CXXMethodDecl *copyAssign = Utils::copyAssign(record);
const bool hasCallableCopyCtor = copyCtor && !copyCtor->isDeleted() && copyCtor->getAccess() != clang::AS_private;
const bool hasCallableCopyAssign = copyAssign && !copyAssign->isDeleted() && copyAssign->getAccess() != clang::AS_private;
if (!hasCallableCopyCtor && !hasCallableCopyAssign)
return;
emitWarning(record->getLocStart(), "Polymorphic class is copyable. Potential slicing.");
}
bool CXXBasePaths::lookupInBases(ASTContext &Context,
const CXXRecordDecl *Record,
CXXRecordDecl::BaseMatchesCallback BaseMatches,
bool LookupInDependent) {
bool FoundPath = false;
// The access of the path down to this record.
AccessSpecifier AccessToHere = ScratchPath.Access;
bool IsFirstStep = ScratchPath.empty();
for (const auto &BaseSpec : Record->bases()) {
// Find the record of the base class subobjects for this type.
QualType BaseType =
Context.getCanonicalType(BaseSpec.getType()).getUnqualifiedType();
// C++ [temp.dep]p3:
// In the definition of a class template or a member of a class template,
// if a base class of the class template depends on a template-parameter,
// the base class scope is not examined during unqualified name lookup
// either at the point of definition of the class template or member or
// during an instantiation of the class tem- plate or member.
if (!LookupInDependent && BaseType->isDependentType())
continue;
// Determine whether we need to visit this base class at all,
// updating the count of subobjects appropriately.
std::pair<bool, unsigned>& Subobjects = ClassSubobjects[BaseType];
bool VisitBase = true;
bool SetVirtual = false;
if (BaseSpec.isVirtual()) {
VisitBase = !Subobjects.first;
Subobjects.first = true;
if (isDetectingVirtual() && DetectedVirtual == nullptr) {
// If this is the first virtual we find, remember it. If it turns out
// there is no base path here, we'll reset it later.
DetectedVirtual = BaseType->getAs<RecordType>();
SetVirtual = true;
}
} else
++Subobjects.second;
if (isRecordingPaths()) {
// Add this base specifier to the current path.
CXXBasePathElement Element;
Element.Base = &BaseSpec;
Element.Class = Record;
if (BaseSpec.isVirtual())
Element.SubobjectNumber = 0;
else
Element.SubobjectNumber = Subobjects.second;
ScratchPath.push_back(Element);
// Calculate the "top-down" access to this base class.
// The spec actually describes this bottom-up, but top-down is
// equivalent because the definition works out as follows:
// 1. Write down the access along each step in the inheritance
// chain, followed by the access of the decl itself.
// For example, in
// class A { public: int foo; };
// class B : protected A {};
// class C : public B {};
// class D : private C {};
// we would write:
// private public protected public
// 2. If 'private' appears anywhere except far-left, access is denied.
// 3. Otherwise, overall access is determined by the most restrictive
// access in the sequence.
if (IsFirstStep)
ScratchPath.Access = BaseSpec.getAccessSpecifier();
else
ScratchPath.Access = CXXRecordDecl::MergeAccess(AccessToHere,
BaseSpec.getAccessSpecifier());
}
// Track whether there's a path involving this specific base.
bool FoundPathThroughBase = false;
if (BaseMatches(&BaseSpec, ScratchPath)) {
// We've found a path that terminates at this base.
FoundPath = FoundPathThroughBase = true;
if (isRecordingPaths()) {
// We have a path. Make a copy of it before moving on.
Paths.push_back(ScratchPath);
} else if (!isFindingAmbiguities()) {
// We found a path and we don't care about ambiguities;
// return immediately.
return FoundPath;
}
} else if (VisitBase) {
CXXRecordDecl *BaseRecord;
if (LookupInDependent) {
BaseRecord = nullptr;
const TemplateSpecializationType *TST =
BaseSpec.getType()->getAs<TemplateSpecializationType>();
if (!TST) {
if (auto *RT = BaseSpec.getType()->getAs<RecordType>())
BaseRecord = cast<CXXRecordDecl>(RT->getDecl());
} else {
TemplateName TN = TST->getTemplateName();
if (auto *TD =
dyn_cast_or_null<ClassTemplateDecl>(TN.getAsTemplateDecl()))
BaseRecord = TD->getTemplatedDecl();
}
if (BaseRecord) {
if (!BaseRecord->hasDefinition() ||
VisitedDependentRecords.count(BaseRecord)) {
BaseRecord = nullptr;
} else {
VisitedDependentRecords.insert(BaseRecord);
}
}
} else {
BaseRecord = cast<CXXRecordDecl>(
BaseSpec.getType()->castAs<RecordType>()->getDecl());
}
if (BaseRecord &&
lookupInBases(Context, BaseRecord, BaseMatches, LookupInDependent)) {
// C++ [class.member.lookup]p2:
// A member name f in one sub-object B hides a member name f in
// a sub-object A if A is a base class sub-object of B. Any
// declarations that are so hidden are eliminated from
// consideration.
// There is a path to a base class that meets the criteria. If we're
// not collecting paths or finding ambiguities, we're done.
FoundPath = FoundPathThroughBase = true;
if (!isFindingAmbiguities())
return FoundPath;
}
}
// Pop this base specifier off the current path (if we're
// collecting paths).
if (isRecordingPaths()) {
ScratchPath.pop_back();
}
// If we set a virtual earlier, and this isn't a path, forget it again.
if (SetVirtual && !FoundPathThroughBase) {
DetectedVirtual = nullptr;
}
}
// Reset the scratch path access.
ScratchPath.Access = AccessToHere;
return FoundPath;
}